Various types of data decoding devices and applications generate digitally based presentations which may be experienced by an individual or group of people. Digitally based presentations may be generated by, for example, digital movie players (e.g., a DVD player), digital music players (e.g., a CD player), World Wide Web browsers, Portable Document Format readers (e.g., ADOBE ACROBAT READER), spread-sheet software, word-processing software, operating system software, and video game players. Such presentations may be multimedia presentations that include some combination of text, graphics, video, animation, and/or sound. In addition, digitally based presentations may be interactive presentations that allow users to enter data or commands.
In the above-described systems, coded audiovisual information is used as input to generate the presentation. In the World Wide Web browser, for example, browser software (such as INTERNET EXPLORER from MICROSOFT Corp.) executing on a general purpose computer may be used to decode HTML pages (i.e., audiovisual information) and generate an interactive multimedia presentation. Typically, the various types of systems require various different coding formats for the audiovisual information. For example, a is World Wide Web browser (“Web browser”) may not be able to operate using data that is formatted for a CD player.
The Moving Picture Expert Group (MPEG) of the International Organization for Standardization (ISO) has introduced standards for coding of audiovisual information. These standards include MP3, MPEG-1, MPEG-2, and MPEG-4. MPEG-4 provides a standard for representing units, known as “media objects,” of aural, visual or audiovisual content. These media objects can be of natural origin (e.g., recorded with a camera or microphone) or synthetic origin (e.g., generated with a computer). MPEG-4 specifies a standard for describing the composition of these objects and for combining these objects to form audiovisual “scenes.” A description of MPEG-4 is set forth in MPEG-4 Standard ISO/IEC, 14496-1, hereby incorporated by reference, as well as in Multimedia Systems, Standards and Networks (Atul Puri and Tsuhan Chen, Editors). An MPEG-4 decoder receives a bit-stream of data that was originally authored by coding media objects according to the MPEG-4 systax. The MPEG-4 decoder then may present the scene specified in the coded data by, for example, displaying the scene on a computer monitor or a television screen. The scene could contain text, graphics, video, animation, and/or sound in any combination.
Many systems and applications that generate digitally based presentations, such as a Web browser or Portable Document Format reader, do not conform to the MPEG-4 standard. In some cases, the author of a scene might want to include the presentation from a non-MPEG-4 application, such as a Web browser, into the scene generated by an MPEG-4 decoder. However, prior to the present invention, MPEG-4 did not provide a method or apparatus by which the author of the scene could integrate an application that does not conform to the MPEG-4 standard into a scene generated by an MPEG-4 decoder.